A magnetic detection apparatus capable of detecting magnetism of a paper sheet being transported is known conventionally. For example, a magnetic detection apparatus is arranged inside a banknote handling apparatus that performs recognition and counting of banknotes. Magnetic characteristics of each of the banknotes are detected by using the magnetic detection apparatus, and authenticity and the like of each of the banknotes is recognized based on the obtained detection result. For example, a plurality of magnetic sensors is arranged in a linear manner inside the magnetic detection apparatus, and the magnetism of the banknotes is detected after performing calibration of those magnetic sensors.
For example, Patent Document 1 discloses an apparatus in which a linear conducting wire is arranged corresponding to the plurality of sensors arranged in a liner manner, and the calibration of each of the magnetic sensors is performed by generating a calibration magnetic field by passing an electric current in this conducting wire. Patent Document 2 discloses an apparatus that generates a calibration magnetic field with a rectangular plate-shaped conductor and performs the calibration of the magnetic sensors.